RELATIONS BETWEEN THE GRAIN HARDNESS AND OTHER QUALITY PARAMETERS OF WHEAT

The tested set for statistical evaluation consists of 191 commercial wheat samples harvested during 2006–2009 in six Bohemia localities. Food wheat was described by quality traits, in emphasis of PSI and NIR hardness, one-stream and fraction milling (grinder FQC 109 and laboratory mill CD1 Auto, respectively). Statistical methods confirmed our hypothesis of wheat hardness importance in quality depending on the external condition. Milling parameters as TW or PSI hardness and baking ones (e.g. protein content or the Zeleny’s value) showed comparable quality oscillation in regards to crop year and locality. Measured PSI hardness of 13–29% corresponded with classification ‘hard’ and ‘medium hard’ (37% of samples sorted into the former and 52% into the latter category). Significant correlations of grain hardness to the gluten content and the flour yield were confirmed (0.35, 0.67 for one-stream and 0.68 for total flour yield, respectively; P = 99%). ANOVA and PCA statistics detected primary impact of harvest year factor on commercial wheat, and as crucial features were found out the gluten and protein contents, the Zeleny’s value, PSI hardness and the one-stream flour yield. According to statistical analysis, grain hardness and flour yield of commercial wheat belong to significant qu ality features with year crop changes